1. Field of the Invention
The present invention relates to a device for automatically switching the color of a luminescent dashboard, and more particularly to a device that is able to sense a reduced luminance in surrounding environment and to automatically actuate a dashboard lamp accordingly, and enables a luminescent dashboard to automatically switch its color when driving speed changes.
2. Description of the Prior Art
Cold light has been widely employed in displays and indicators as a back light and/or illuminating light in recent years. For example, cold light can be used in a dashboard to provide backlight for a backboard 230 and/or meters 210 of the dashboard, as shown in FIG. 1. In the case of a digital meter, the cold light may also be used to illuminate readings shown on the meter. And, in the case of a needle indicator, the cold light may be used as backlight of the indicator to work with a needle 220 applied with fluorescent material.
In conventional techniques, the cold light employed on dashboard is monochromatic light. To change the color of the cold light, a manual control is required. Since the cold light could be used only as illuminating light without other functions and a dashboard lamp illuminated with cold light must be manually actuated, it is apparent a conventional luminescent dashboard, that is, a dashboard with cold light as its backlight, does not meet the demand of nowadays society.
It is therefore desirable to develop an improved luminescent dashboard.
A primary object of the present invention is to provide a device for automatically switching the color of a luminescent dashboard when the driving speed changes. When a car moves at high speed, the device of the present invention enables a luminescent dashboard of the car to automatically change its color as a warning to the driver to avoid accident. Therefore, the luminescent dashboard functions like an additional driving speed indicator. For example, a driver on a freeway can easily know whether his or her driving speed is within the speed limit simply by seeing the color of the luminescent dashboard. That is, the device of the present invention has functions of automatically detecting and displaying driving speed.
To achieve the above object, the device of the present invention mainly includes:
a driving power source;
a commutating circuit connected to an output of the driving power source and generally composed of a current limiter, an oscillating circuit, and a transformer for providing stable driving power output;
a voltage control circuit having an input connected to the driving power source and generally composed of a voltage controller, a digital controller, a voltage attenuator, and a frequency controller; the voltage control circuit having an output connected to the commutating circuit with the frequency controller connected to the transformer of the commutating circuit, so as to provide different voltages and frequencies for actuating cold light of different colors;
a luminescent device connected to an output of the commutating circuit to show cold light of different colors in response to variable voltages and variable frequencies provided by the commutating circuit; and
a display device connected to an output of the frequency controller for displaying numerals on meters mounted on the luminescent dashboard.
Another object of the present invention is to provide a device for automatically switching the color of a luminescent dashboard that also enables automatic and/or manual actuation of a dashboard lamp when the device senses a reduced luminance in surrounding environment.
To achieve the second object, the device of the present invention provided to achieve the first object further includes a cold light actuating circuit generally composed of a luminance sensor, a trigger circuit, and an electronic switch for connecting to the commutating circuit, so as to automatically actuate the luminescent device for illuminating purpose when the surrounding environment is dark.
To achieve the above objects, the device for automatically switching the color of a luminescent dashboard according to the present invention may also alternatively include:
a driving power source that may be a battery;
a control circuit generally composed of a headlight switch assembly, a current limiter, and an oscillating circuit for adjusting current and outputting control instructions;
a trigger switch circuit generally composed of a luminance sensor, a trigger circuit (Schmidt trigger), and an electronic switch for actuating the electronic switch when a specific luminance is sensed;
a voltage/frequency control circuit mainly composed of a driving control computer, a voltage-stabilizing IC, a digital controller, an increment key, a decrement key, a voltage attenuator, and a frequency controller;
wherein the driving control computer provides information about driving speed, the increment key, the decrement key, and the voltage attenuator together control a magnitude of output voltage, and the digital controller outputs variable-frequency signals to the frequency controller; and
an auto-connected boosting transformer for receiving the output signal from the control circuit and the output voltage and output frequency from the voltage/frequency control circuit in order to operate a luminescent member, and feeding any obtained information back to the control circuit.
By providing the commutating circuit, the voltage control circuit, and the frequency controller, it is possible for the device of the present invention to output variable voltages and frequencies for actuating cold light of different colors. Since the output voltage and the frequency change with driving speed, cold light of different colors are shown when the driving speed changes. And, with the cold light actuating circuit, the luminescent device is automatically actuated to provide illuminating cold light when the surrounding environment becomes dark.